A magnetoresistance effect element having a ferromagnetic layer as a magnetization free layer, a nonmagnetic spacer layer, and a ferromagnetic layer as a magnetization fixed layer, such as a giant magnetoresistance (GMR) effect element and a tunnel magnetoresistance (TMR) effect element, are known. Such a magnetoresistance effect element is used in a device such as a magnetic sensor, a magnetic head, and a magnetoresistance random access memory (MRAM).
Magnetoresistance effect elements currently in practical use have a configuration in which a magnetization free layer, a nonmagnetic spacer layer, and a magnetization fixed layer are stacked in this order. However, in recent years, magnetoresistance effect elements having a configuration in which a magnetization free layer and a magnetization fixed layer are provided on an upper surface of a channel layer composed of a nonmagnetic material have received attention (for example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2010-287666) and Patent Document 2 (WO 2015/076187)). In the magnetoresistance effect elements described in Patent Document 1 and Patent Document 2, the magnetization free layer and the magnetization fixed layer are formed on substantially the same plane, spin-polarized electrons injected from the magnetization free layer or the magnetization fixed layer into the channel layer transport or diffuse in the channel layer, and spins accumulate in the channel layer. According to the magnetoresistance effect element having such a configuration, it is expected that a high spatial resolution will be able to be obtained when it is applied to a magnetic sensor such as a magnetic head or the like on the basis of structural differences from a conventional magnetoresistance effect element, and it is also expected that a degree of freedom in a device design can be improved when it is applied to a device.